Package ‘adfExplorer’
November 3, 2017 Type Package Title Import from and Export to Amiga Disk Files Version 0.1.2 Date 2017-11-03 Author Pepijn de Vries [aut, cre, dtc] Maintainer Pepijn de Vries
R topics documented:
adf.disk.name ...... 2 adf.example ...... 3 adf.file.exists ...... 4
1 2 adf.disk.name
amigaBlock-class ...... 5 amigaBlock-method ...... 5 amigaDateToRaw ...... 7 amigaDisk-class ...... 8 amigaIntToRaw ...... 9 blank.amigaDOSDisk ...... 10 boot.block.code ...... 12 current.adf.dir ...... 13 displayRawData ...... 14 get.adf.file ...... 15 get.blockID ...... 17 get.diskLocation ...... 18 is.amigaDOS ...... 19 is.bootable ...... 20 list.adf.files ...... 21 print ...... 22 rawToAmigaDate ...... 23 rawToAmigaInt ...... 24 read.adf ...... 25 write.adf ...... 27
Index 29
adf.disk.name Get or set the disk name of an amigaDisk object
Description Get or set the disk name of an amigaDisk object.
Usage ## S4 method for signature 'amigaDisk' adf.disk.name(x)
## S4 replacement method for signature 'amigaDisk,character' adf.disk.name(x) <- value
Arguments x An amigaDisk object for which the disk name needs to be obtained or changed. value A character representation with which the disk’s name needs to be replaced. Disk name needs to be between 1 and 30 characters long and are not allowed to contain a colon or forward slash.
Details DOS-formatted disks (is.amigaDOS) store their disk name on the socalled root block of the disk. This method allows you to obtain the disk’s name or change it (when it is DOS-formatted). adf.example 3
Value
Returns A character representation of the disk’s name.
Author(s)
Pepijn de Vries
Examples
## Not run: data(adf.example)
## get the disk name: adf.disk.name(adf.example)
## change it if you don't like it: adf.disk.name(adf.example) <- "MyDisk"
## confirm that it has changed: adf.disk.name(adf.example)
## End(Not run)
adf.example An example of an amigaDisk object
Description
An example of an amigaDisk-class object.
Format
An S4 amigaDisk-class object.
Details
An amigaDisk-class object that represents an ’Old File System’ formatted and bootable disk. It is used in multiple examples of this package. It contains a directory structure and some files that can be accessed using this package. The content of this example might change in future versions.
Examples
data("adf.example") 4 adf.file.exists
adf.file.exists Test file or directory existsence in an amigaDisk object
Description
Tests whether a specific file (or directory) exists in an amigaDisk object.
Usage
## S4 method for signature 'amigaDisk,character' adf.file.exists(x, file)
Arguments
x An amigaDisk object in which this method will check for the file’s existence. file A character string representing a file or directory name. Use Amiga specifica- tions for file name (see current.adf.dir).
Details
This method will look for a file/directory header, based on its name. If such a header exists, it is assumed that the file exists. The file/directory itself is not checked for validity.
Value
Returns a logical value indicating whether the file exists or not.
Author(s)
Pepijn de Vries
Examples
data(adf.example)
## This file exists: adf.file.exists(adf.example, "df0:mods/mod.intro")
## This file doesn't: adf.file.exists(adf.example, "df0:idontexist") amigaBlock-class 5
amigaBlock-class The amigaBlock class
Description The Commodore Amiga stores data on floppy disks as 512 byte blocks. This class reflects such a block.
Details There are several types of blocks. Most important are the boot block (used for booting the Amiga system), the root block (containing information on the disk and the root directory), header blocks (indicating where to find file data) and data blocks (containing the actual file data). See this pack- age’s vignette for more details. use the amigaBlock-method to extract a specific block from an amigaDisk object.
Slots data The raw data of a ’block’ of data on an Amiga disk file. Each block holds 512 bytes of information. This slot is therefore a vector of the same length.
Author(s) Pepijn de Vries
Examples ## create a block with no data: new("amigaBlock")
amigaBlock-method Extract block from or replace a block on an amigaDisk object
Description Extract an amigaBlock from an amigaDisk object, or replace it on the disk.
Usage ## S4 method for signature 'amigaDisk,numeric' amigaBlock(x, block)
## S4 replacement method for signature 'amigaDisk,numeric,amigaBlock' amigaBlock(x, block) <- value 6 amigaBlock-method
Arguments
x An amigaDisk object from which the block needs to be extracted or on which the block needs to be replaced. block A numeric identifier (whole numbers ranging from 0 up to 1759 (DD disk) or 3519 (HD disk)). value An amigaBlock object with which the block at the specified location on the disk needs to be replaced.
Details
Information is stored in 512 byte blocks on floppy disks. This method extracts a specific block at a numeric identifier (whole numbers ranging from 0 up to 1759 (DD disk) or 3519 (HD disk)) from an amigaDisk object.
Value
The amigaBlock object at the specified location is returned. In case of the replace method, an amigaDisk object with a replaced amigaBlock is returned.
Author(s)
Pepijn de Vries
See Also
Other block.operations: get.blockID, get.diskLocation
Examples
## get the root block from the example adf: amigaBlock(adf.example, 880)
## Create a completely blank disk without file system: blank.disk <- new("amigaDisk")
## Replace the boot block on the blank disk with ## that from the example object: amigaBlock(blank.disk, 0) <- amigaBlock(adf.example, 0)
## The blank disk now has a boot block, ## but still no file system... amigaDateToRaw 7
amigaDateToRaw Convert date time objects into raw values
Description This function converts date-time objects into raw data conform Amiga file system specifications.
Usage amigaDateToRaw(x, format = c("long", "short"), tz = "UTC")
Arguments x A(vector of) POSIXt object(s). format a character string indicating whether the date should be stored as short or long integers. tz A character string specifying the time zone to be used to convert the date time object. Note that the time zone is not stored on the Amiga. By default the Universal time zone (UTC) is assumed. You will get a warning when you use a timezone other then UTC.
Details The Amiga file system stores date time objects as three unsigned short (16 bit) or long (32 bit) integers. Where the values are number of days, minutes and ticks (fiftieth of a second) since 1978- 01-01 respectively. As these values are always positive, only date time values on or after 1978-01-01 are allowed. The inverse of this function can be achieved with rawToAmigaDate.
Value returns raw data reflecting the date-time objects conform the Amiga file system specifications.
Author(s) Pepijn de Vries
See Also Other raw.operations: amigaIntToRaw, displayRawData, rawToAmigaDate, rawToAmigaInt
Examples ## Note that using the same date-time with different timezones will ## result in different raw data. The time zone is not stored. amigaDateToRaw(as.POSIXct("1978-01-01 13:30", tz = "UTC")) amigaDateToRaw(as.POSIXct("1978-01-01 13:30", tz = "CET")) 8 amigaDisk-class
amigaDisk-class The amigaDisk class
Description
An S4 class representing the information from an Amiga Disk File.
Details
An Amiga Disk File (ADF) holds the raw data of an amiga disk in the same order as blocks (amigaBlock-class) on the physical disks. As an Amiga Disk can hold any kind of information, so can this class. An ADF file does not hold any other information. The size of the file will dictate whether it repre- sents a double density floppy disk (880 kB) or a high density floppy disk (1760 kB). The disk type is also stored in this class. Finally, the current directory is stored with this class. Which is only useful for DOS-formatted disks (with a file structure). By default this is set to the disk’s root. For more (technical) backgrounds please check this package’s vignette. Use the objects constructor (new("amigaDisk")) to create a completely blank disk (without a filesystem). If you want to be able to transfer files from and to the virtual disk, use blank.amigaDOSDisk instead.
Slots
data The raw data of the virtual disk. It should be a vector of length 901,120 in case of a double density disk and 1,802,240 in case of a high density disk. type A character indicating whether the virtual disk represents a "DD" (double density, most common) or "HD" (high density) disk. current.dir An integer, pointing at the block address of the current directory of this virtual disk. Use current.adf.dir to get or set the current directory.
Author(s)
Pepijn de Vries
Examples
## This creates a blank non-bootable, non-DOS disk: new("amigaDisk") amigaIntToRaw 9
amigaIntToRaw Convert Amiga integers into raw values
Description Convert 8, 16, or 32-bit signed or unsigned integer values into raw data, conform Amiga specifica- tions.
Usage amigaIntToRaw(x, bits = 8, signed = F)
Arguments x A vector of class numeric which needs to be converted into raw values. bits Number of bits that represents the integer value. Should be 8 or a positive mul- titude of 8. signed A logical value indicating whether the numeric values is signed (TRUE, default) or not (FALSE).
Details The Commodore Amiga has specified the following data formats to represent integer data: BYTE (signed 8-bit integer), UBYTE (unsigned 8-bit integer), WORD (signed 16-bit integer), UWORD (unsigned 16-bit integer), LONG (signed 32-bit integer), ULONG, (unsigned 32-bit integer). This function converts such integers into raw data.
Value Returns (a vector of) raw data, representing the integer value(s) conform Amiga specifications.
Author(s) Pepijn de Vries
See Also Other raw.operations: amigaDateToRaw, displayRawData, rawToAmigaDate, rawToAmigaInt
Examples ## some unsigned 8-bit integers: ubyte <- sample.int(255, 100, TRUE)
## The same values as raw data: amigaIntToRaw(ubyte)
## some signed 8-bit integers: 10 blank.amigaDOSDisk
byte <- sample.int(255, 100, TRUE) - 128
## The same values as raw data: amigaIntToRaw(byte, signed = TRUE)
## some signed 16-bit integers: word <- sample.int(2^16, 100, TRUE) - 2^15
## The same values as raw data: amigaIntToRaw(word, 16, TRUE)
## note that 16-bit integers require ## twice as many raw values: length(amigaIntToRaw(word, 16, TRUE)) length(amigaIntToRaw(byte, 8, TRUE))
blank.amigaDOSDisk Create blank disk with file system
Description Create a virtual blank DOS formatted floppy disk with a file system on it.
Usage ## S4 method for signature 'character' blank.amigaDOSDisk(diskname, disktype = c("DD", "HD"), filesystem = c("OFS", "FFS"), international = F, dir.cache = F, bootable = T, creation.date = Sys.time())
Arguments diskname A character string of the desired disk name. Disk name should be between 1 and 30 characters long, and should not contain any colon or forward slash characters. disktype Either "DD" (double density, most common and therefore default) or "HD" (high denisity). The type of disk the blank disk should represent. filesystem Either "OFS" (old file system) or "FFS" (fast file system). FFS is not compatible with Amiga OS <2.0. On the original system, the FFS was slightly faster and can requires less data for the file system. It is however less robust: on corrupt disks, file recovery is more difficult. international The international mode was introduced in Amiga OS 2.0. In lower versions, international characters were mistakenly not converted to uppercase when com- paring file names. The international mode (set this argument to TRUE) corrects this mistake. The international mode is not compatible with Amiga OS <2.0. blank.amigaDOSDisk 11
dir.cache The directory cache mode (set this argument to TRUE) was introduced with Amiga OS 3.0 (and is not compatible with lower versions). On real machines this allowed for slightly faster directory listing (but costs disk space). The direc- tory cache mode is always used in combination with the ’international mode’. bootable When this argument is set to TRUE. Minimal executable code is added to the bootblock. This code will open the command line interface when the disk is used to boot the system. In Amiga OS >2.0, the ’Startup-Sequence’ file needs to be present for this, otherwise the screen will remain black on booting. See also the boot.block.code data. creation.date A POSIXt object. Will be used and stored as the creation date of the virtual disk. Note that the Amiga does not store the time zone and UTC is assumed as default. The Amiga stores the date and time as positive integers, relative to 1st of January in 1978. As a result, dates before that are not allowed.
Details Creates a blank link{amigaDisk} object. This method differs from the object constructor (new("amigaDisk")) because it also installs a file system on the disk. The blank disk can thus be used to write files onto, and is also usable in Amiga emulators. For use in emulators, the object needs to be saved with the write.adf method.
Value Returns a blank amigaDisk object with a file system installed on it.
Author(s) Pepijn de Vries
Examples ## Create a blank virtual disk compatible with ## Amiga OS 1.x and up (Note that spaces in file and ## disk names are allowed but not recommended): disk.os1x <- blank.amigaDOSDisk(diskname = "I'm_OS_1.x_compatible", disktype = "DD", filesystem = "OFS", international = FALSE, dir.cache = FALSE, bootable = TRUE)
## create a disk that is compatable with OS 2.x and up ## (no backward compatability): disk.os2x <- blank.amigaDOSDisk(diskname = "I'm_OS_2.x_compatible", disktype = "DD", filesystem = "FFS", international = TRUE, dir.cache = FALSE, bootable = TRUE) 12 boot.block.code
## create a disk that is compatable with OS 3.x and up ## (no backward compatability): disk.os3x <- blank.amigaDOSDisk(diskname = "I'm_OS_3.x_compatible", disktype = "DD", filesystem = "FFS", international = TRUE, dir.cache = TRUE, bootable = TRUE)
boot.block.code Minimal executable code for a bootblock
Description A minimal piece of code required to boot to a command line interface on a Commodore Amiga.
Format A data frame with two columns. The first column contains the assembled code (as raw data). The second column contains the corresonding Motorola 68000 (the main CPU of the original Com- modore Amiga) assembly syntax.
Details The first two blocks (amigaDisk) are special and are called the boot block. This block should contain information on the type of disk and possibly some executable code that will be run at boot time. This data.frame contains some minimal executable code that will start the Amiga command line interface. On Amiga OS >=2.0 the screen will stay black unless a startup-sequence file is present on the disk. The original code is from Thomas Kessler as published by Laurent Clévy (http://lclevy.free. fr/adflib/adf_info.html).
Examples
data("boot.block.code")
## To create a basic boot block for a DD disk: bblock <- new("amigaBlock", data = c(as.raw(c(0x44, 0x4F, 0x53, 0x00, 0xE3, 0x3D, 0x0E, 0x73, 0x00, 0x00, 0x03, 0x70)), unlist(boot.block.code$assembled), raw(419)) ) ## The raw data preceding the executable code are ## a label, flags and a checksum. current.adf.dir 13
current.adf.dir Get or set the current directory of an amigaDisk object
Description Get or set the current directory of an amigaDisk object.
Usage ## S4 method for signature 'amigaDisk' current.adf.dir(x)
## S4 replacement method for signature 'amigaDisk,character' current.adf.dir(x) <- value
Arguments x An amigaDisk object for which the current directory needs to be obtained or changed. value A character representation of the path, that needs to be set as current directory. Use Amiga DOS syntax as specified in the details
Details By default the disk’s root is stored as the current directory for a new amigaDisk object. With this method, the current directory can be retrieved or changed. For this purpose the path should be specified conform Amiga DOS syntax. Use the disk’s name or "DF0" followed by a colon in order to refer to the disk’s root. Subdirectories are separated by forward slashes ("/"). Colons and forward slashes are not allowed in file and directory names. Both upper and lowercase letters are allowed in file and directory names. The case is ignored when iden- tifying files however. This packages will NOT follow the Amiga’s full search path (http://wiki. amigaos.net/wiki/AmigaOS_Manual:_AmigaDOS_Working_With_AmigaDOS#Search_Path).
Value Returns a character representation of the current directory.
Author(s) Pepijn de Vries
Examples data(adf.example)
## by default the current dir is the ## disk's root. The disk name is 14 displayRawData
## therefore shown when running ## current.adf.dir for the provided ## example data:
current.adf.dir(adf.example)
## change the current dir: current.adf.dir(adf.example) <- "DF0:this/is/a/deep/path"
## confirm that it has changed: current.adf.dir(adf.example)
## let's set it back to the disk's root: current.adf.dir(adf.example) <- "DF0:"
displayRawData Display raw data in a comprehensive way
Description Cat raw data to the sink in columns with ASCII code
Usage displayRawData(x, ncol = 4, col.wid = 4, address.len = 3, hex.upper = T)
Arguments x A vector of class raw to be displayed. ncol Number of columns of hexadecimal code to display. col.wid Width of each column (in bytes) to display. address.len Length of the hexadecimal address (in number of hexadecimal digits) to display. hex.upper logical value, to specify whether hexadecimals should be displayed in upper- case (TRUE, default) or lowercase (FALSE).
Details As binary data is hard to decipher this function will cat raw data as hexadecimal code in columns, together with the relative (hexadecimal) address of the data and an ASCII translation of the data. Hexadecimals are shown in space separated columns for improved readability. Special characters are replaced by dots in the ASCII representation. Raw data is padded with zeros at the end to fill remaining columns...
Value The character string send to the sink is also returned by the function. get.adf.file 15
Author(s) Pepijn de Vries
See Also Other raw.operations: amigaDateToRaw, amigaIntToRaw, rawToAmigaDate, rawToAmigaInt
Examples ## Display some raw random data: displayRawData(as.raw(sample.int(100)))
## Display the full ASCII table: displayRawData(as.raw(0:255))
get.adf.file Get a file from an amigaDisk object
Description Get files stored on virtual amigaDisks as raw data or copy as file.
Usage ## S4 method for signature 'amigaDisk,character,missing' get.adf.file(x, source, destination)
## S4 method for signature 'amigaDisk,character,character' get.adf.file(x, source, destination)
## S4 method for signature 'amigaDisk,character,ANY' get.adf.file(x, source, destination)
Arguments x An amigaDisk object from which a file needs to be extracted. source Specify the source file’s path on the amigaDisk object, conform Amiga specs. See current.adf.dir for details on these specs. destination either a file name or a file connection, that allows writing binary data (see e.g., file or url). When the destination is missing, the file content is returned as raw data.
Details Amiga DOS formatted disks can store any kind of file (as long as the disk’s capacity allows it). Use this method to extract such files embedded in an Amiga Disk File (ADF) as raw data or copy to a file on your system. 16 get.adf.file
Value
Returns a vector of raw data when the argument destination is missing. Otherwise returns nothing.
Author(s)
Pepijn de Vries
Examples
data(adf.example)
## Not run: ## get the file "Startup-Sequence" from the virtual ## example disk and save as a text file in the ## current working directory: get.adf.file(adf.example, "DF0:S/Startup-Sequence", "startup.txt")
## End(Not run)
## get the same file as raw data ## by omitting the destination: startup <- get.adf.file(adf.example, "DF0:S/Startup-Sequence")
## Look, it's a text file: cat(rawToChar(startup))
if (requireNamespace("ProTrackR", quietly = TRUE)) { ## look there is a typical ProTracker module on ## the example disk. You can load it like this:
## get the file from the virtual disk ## as raw data mod.raw <- get.adf.file(adf.example, "DF0:mods/mod.intro")
## open a raw connection with the ## newly imported raw data con <- rawConnection(mod.raw, "rb")
## and read it as a ProTracker module mod <- ProTrackR::read.module(con) close(con)
## plot the first sample from the module: plot(ProTrackR::waveform(ProTrackR::PTSample(mod, 1)), type = "l", ylab = "amplitude") } else { cat("You need to install and load the\nProTrackR package for this part of the example.") } get.blockID 17
get.blockID Get the block ID from the physical location on the disk
Description
Get the block identifier based on the physical location on a disk (side, cylinder and sector) and the disk type.
Usage ## S4 method for signature 'character,numeric,numeric,numeric' get.blockID(disktype, sector, side, cylinder)
Arguments
disktype A character string indicating the type of disk: DD for double density disks. HD for high density disks. sector numeric identifier for the sector on the disk, ranging from 0 up to 10 (DD disks) or 21 (HD disks). side numeric identifier for the side of the disk (0 or 1). cylinder numeric identifier for the cylinder on the disk, ranging from 0 up to 79.
Details
Data on amiga floppy disks are stored as 512 byte blocks. These blocks are physically stored on a specific cylinder and side at a specific sector. This method returns the block identifier based on the physical location on the disk. The inverse of this function is achieved with the get.diskLocation method. Note that all identifiers (or indices) have a base at zero, for consitency with Amiga specifications and documentation, opposed to the base of one used in R.
Value
Returns the numeric identifier for the corresponding block.
Author(s)
Pepijn de Vries
See Also
Other block.operations: amigaBlock-method, get.diskLocation 18 get.diskLocation
Examples ## Get the block identifier for sectors 0 up to 3 combined with ## cylinders 0 up to 3 on side 0 of the disk: get.blockID(disktype = "DD", sector = 0:3, side = 0, cylinder = 0:3)
get.diskLocation Get the physical location on the disk for a specific block
Description Get the side, cylinder and sector on a disk, based on disk type and block id.
Usage ## S4 method for signature 'character,numeric' get.diskLocation(disktype, block)
Arguments disktype A character string indicating the type of disk: DD for double density disks. HD for high density disks. block numeric identifier of a block. Whole numbers ranging from 0 up to 1759 (for DD disks) or 3519 (for HD disks). Note that the base index is zero (for consi- tency with Amiga specifications and documentation) opposed to the base of one used in R.
Details Data on amiga floppy disks are stored as 512 byte blocks. These blocks are physically stored on a specific cylinder and side at a specific sector. This method returns the identifiers for the physical location based on the block identifier. The inverse of this function is achieved with the get.blockID method.
Value Returns a list with corresponding sector, side and cylinder identifiers (numeric).
Author(s) Pepijn de Vries
See Also Other block.operations: amigaBlock-method, get.blockID is.amigaDOS 19
Examples
## get the physical location of the first 20 blocks on a DD disk ## and arrange as a data.frame: as.data.frame(get.diskLocation("DD", 0:19))
is.amigaDOS Check if amigaDisk object is DOS formatted
Description This method checks if there is a DOS file structure is present on the amigaDisk object.
Usage ## S4 method for signature 'amigaDisk' is.amigaDOS(x)
Arguments x An amigaDisk object for which the check should be performed.
Details Not all Amiga Disk Files have a DOS file structure on them. This function checks if there is.
Value Returns a logical value, indicating whether the disk is DOS formatted. When it is not, the at- tributes to the returned value will contain information as to why the disk is not DOS compatible.
Author(s) Pepijn de Vries
Examples
data(adf.example)
## let's check if the example amigaDisk object ## is DOS formatted:
is.amigaDOS(adf.example)
## it apparently is 20 is.bootable
is.bootable Check if amigaDisk object is bootable
Description
This function checks if the amigaDisk object represents a bootable disk.
Usage ## S4 method for signature 'amigaDisk' is.bootable(x)
Arguments
x An amigaDisk object for which the check should be performed.
Details
The first two amigaBlock-class objects on a disk are special and are called the boot block. The boot block will determine whether an Amiga can boot from the disk. This function will determine whether the Amiga would attempt to execute the machine code present on the boot block. It will not check whether it would be successful at that, as that would require emulation of the Commodore Amiga system.
Value
Returns a logical value, indicating whether the disk is bootable.
Author(s)
Pepijn de Vries
Examples
data(adf.example)
## let's check if the example amigaDisk object ## is bootable:
is.bootable(adf.example)
## it apparently is list.adf.files 21
list.adf.files List files in an amigaDisk directory
Description Get a list of files in a specific directory on a virtual amigaDisk.
Usage ## S4 method for signature 'amigaDisk,missing' list.adf.files(x, path)
## S4 method for signature 'amigaDisk,character' list.adf.files(x, path)
Arguments x An amigaDisk object for which the files should be listed. path Specify the path on the amigaDisk object, conform Amiga specs, for which files should be listed. See current.adf.dir for details on these specs.
Details As an analogue of list.files, this method list files in a specific directory. But in this case the files are located on a virtual floppy disk represented by the amigaDisk object. This works only for DOS-formatted (is.amigaDOS) virtual disks.
Value Returns a vector of characters listing the files in the specified directory on the virtual disk.
Author(s) Pepijn de Vries
Examples data(adf.example)
## show all files in the root of the example ## disk file: list.adf.files(adf.example)
## you can also list the files in a specified ## directory: list.adf.files(adf.example, "DF0:mods")
## For the same path, only now specified 22 print
## relatively to the current directory: list.adf.files(adf.example, "mods")
print Print Amiga Disk File objects
Description
A method to print Amiga Disk File S4 class objects to the sink.
Usage
## S4 method for signature 'amigaDisk' print(x, ...)
## S4 method for signature 'amigaBlock' print(x, ...)
Arguments
x Either a amigaDisk or amigaBlock object. ... further arguments passed to or from other methods
Value
Returns nothing (NULL).
Author(s)
Pepijn de Vries
Examples
data(adf.example)
print(adf.example) rawToAmigaDate 23
rawToAmigaDate Convert raw values into a date time object
Description This function converts raw data into a date time object conform the Amiga file system specifications.
Usage rawToAmigaDate(x, format = c("long", "short"), tz = "UTC")
Arguments x a vector of raw values with a length of a multitude of 6 (for the short format) or 12 (for the long format). format a character string indicating whether the date is stored as short or long inte- gers. tz A character string specifying the time zone to be used to retrieve the date time object. Note that the time zone is not stored on the Amiga. By default the Universal time zone (UTC) is assumed.
Details The Amiga file system stores date time objects as three unsigned short (16 bit) or long (32 bit) integers. Where the values are number of days, minutes and ticks (fiftieth of a second) since 1978- 01-01 respectively. As these values are always positive, only date time values on or after 1978-01-01 are allowed. The inverse of this function can be achieved with amigaDateToRaw.
Value Returns a POSIXct object based on the provided raw data.
Author(s) Pepijn de Vries
See Also Other raw.operations: amigaDateToRaw, amigaIntToRaw, displayRawData, rawToAmigaInt
Examples ## all raw data is zero, so the origin date is returned: rawToAmigaDate(raw(12))
## let's get the date, one day, one minute and 50 ticks from the origin: rawToAmigaDate(amigaIntToRaw(c(1, 1, 50), 32)) 24 rawToAmigaInt
rawToAmigaInt Convert raw values into Amiga integers
Description
Convert raw data into 8, 16, or 32-bit signed or unsigned integer values, conform Amiga specifica- tions.
Usage
rawToAmigaInt(x, bits = 8, signed = F)
Arguments
x A vector of class raw to be converted into a character. bits Number of bits that represents the integer value. Should be 8 or a positive mul- titude of 8. signed A logical value indicating whether the integer should be signed (TRUE, default) or not (FALSE).
Details
The Commodore Amiga has specified the following data formats to represent integer data: BYTE (signed 8-bit integer), UBYTE (unsigned 8-bit integer), WORD (signed 16-bit integer), UWORD (unsigned 16-bit integer), LONG (signed 32-bit integer), ULONG, (unsigned 32-bit integer). This function converts raw data into such integers. Note that WORD and UWORD are also referred to as SHORT and USHORT respectively.
Value
A numeric value (or a vector of values), representing the integer data represented by the provided raw data. Note that R defines integer as 32-bit signed integers and cannot store the 32-bit signed values. Therefore a numeric value is returned rather than an explicit integer.
Author(s)
Pepijn de Vries
See Also
Other raw.operations: amigaDateToRaw, amigaIntToRaw, displayRawData, rawToAmigaDate read.adf 25
Examples ## Let's start by obtaining unsigned 8-bit integers: rawToAmigaInt(as.raw(0:255))
## note that this is the same as: as.numeric(as.raw(0:255))
## but with this function we can also get signed values: rawToAmigaInt(as.raw(0:255), signed = TRUE)
## Furthermore 32 or 16-bit integers can also be obtained. ## Let's look at 16-bit integers: rawToAmigaInt(as.raw(0:255), 16)
## Note that 16-bit integers require twice as many bytes ## as 8 bit integers: length(rawToAmigaInt(as.raw(0:255), 16)) length(rawToAmigaInt(as.raw(0:255), 8))
read.adf Read an Amiga Disk File
Description Read data from an Amiga Disk File (ADF) to an amigaDisk object. Alternatively data can be read from an ADZ file.
Usage ## S4 method for signature 'character' read.adf(file)
## S4 method for signature 'ANY' read.adf(file)
## S4 method for signature 'character' read.adz(file)
Arguments file Either a file name or a file connection, that allows reading binary data (see e.g., file or url). read.adz only accepts file names.
Details Amiga Disk Files usually have a .adf-extension to the file name. It should be 880 kB (double density) or 1760 kB (high density) in size. This function can read such files. Alternatively, ADZ files can also be read. These are essentially gzipped ADF files. 26 read.adf
Note that this package cannot read extended ADF files containing information on the disk’s Mod- ified frequency modulation (MFM). This information is typically only required for copy protected disk’s and is therefore out of the scope of this package.
Value
Returns an amigaDisk object read from the provided amiga disk file
Author(s)
Pepijn de Vries
See Also
Other io.operations: write.adf
Examples
## Not run: ## In order to read an adf-file, we first need one. ## so let's first write the example obect to a file: data(adf.example)
## write it to the current working directory: write.adf(adf.example, "test.adf")
## now we can read it again: my.disk <- read.adf("test.adf") print(my.disk)
## and this is how you read it, ## using a connection: con <- file("test.adf", "rb") my.disk2 <- read.adf(con) close(con)
print(my.disk2)
## Alternatively, you can work with ADZ files: write.adz(adf.example, "test.adz") my.disk3 <- read.adz("test.adz")
print(my.disk3)
## End(Not run) write.adf 27
write.adf Write an amigaDisk object to an ADF file
Description
Write an amigaDisk object to an Amiga Disk File (ADF) or alternatively to an ADZ file.
Usage
## S4 method for signature 'amigaDisk,ANY' write.adf(x, file)
## S4 method for signature 'amigaDisk,character' write.adf(x, file)
## S4 method for signature 'amigaDisk,character' write.adz(x, file)
Arguments
x An amigaDisk object that needs to be saved to an ADF file. file either a file name to write to, or a file connection, that allows to write binary data (see file). write.adz only accepts a file name.
Details
Use this function to write amigaDisk objects as binary data to so-called Amiga Disk Files (ADF). These files can be used as input for Amiga emulator software. Alternatively, the object can be saved with ’write.adz’, which is essentially a gzipped version of an ADF file.
Value
Writes to an ADF file but returns nothing.
Author(s)
Pepijn de Vries
See Also
Other io.operations: read.adf 28 write.adf
Examples ## Not run: ## Let's write the example data to an ADF file: data(adf.example)
## Let's put it in the current working directory: write.adf(adf.example, "test.adf")
## You can also use file connections to do the same: con <- file("test2.adf", "wb") write.adf(adf.example, con) close(con)
## Last but not least the same object can be saved ## as an adz file: write.adz(adf.example, "test.3.adz")
## End(Not run) Index
adf.disk.name,2 get.adf.file, 15 adf.disk.name,amigaDisk-method get.adf.file,amigaDisk,character,ANY-method (adf.disk.name),2 (get.adf.file), 15 adf.disk.name<- (adf.disk.name),2 get.adf.file,amigaDisk,character,character-method adf.disk.name<-,amigaDisk,character-method (get.adf.file), 15 (adf.disk.name),2 get.adf.file,amigaDisk,character,missing-method adf.example,3 (get.adf.file), 15 adf.file.exists,4 get.blockID, 6, 17, 18 adf.file.exists,amigaDisk,character-method get.blockID,character,numeric,numeric,numeric-method (adf.file.exists),4 (get.blockID), 17 amigaBlock, 5,6 , 22 get.diskLocation, 6, 17, 18 amigaBlock (amigaBlock-class),5 get.diskLocation,character,numeric-method amigaBlock,amigaDisk,numeric-method (get.diskLocation), 18 (amigaBlock-method),5 amigaBlock-class,5 is.amigaDOS, 2, 19, 21 amigaBlock-method,5 is.amigaDOS,amigaDisk-method amigaBlock<- (amigaBlock-method),5 (is.amigaDOS), 19 amigaBlock<-,amigaDisk,numeric,amigaBlock-methodis.bootable, 20 (amigaBlock-method),5 is.bootable,amigaDisk-method amigaDateToRaw,7, 9, 15, 23, 24 (is.bootable), 20 amigaDisk, 2, 4–6, 11–13, 15, 19–22, 25–27 amigaDisk (amigaDisk-class),8 list.adf.files, 21 amigaDisk-class,8 list.adf.files,amigaDisk,character-method amigaIntToRaw, 7,9, 15, 23, 24 (list.adf.files), 21 list.adf.files,amigaDisk,missing-method blank.amigaDOSDisk, 8, 10 (list.adf.files), 21 blank.amigaDOSDisk,character-method list.files, 21 (blank.amigaDOSDisk), 10 boot.block.code, 11, 12 POSIXct, 23 POSIXt, 7, 11 current.adf.dir, 4, 8, 13, 15, 21 print, 22 current.adf.dir,amigaDisk-method print,amigaBlock-method (print), 22 (current.adf.dir), 13 print,amigaDisk-method (print), 22 current.adf.dir<- (current.adf.dir), 13 current.adf.dir<-,amigaDisk,character-method rawToAmigaDate, 7, 9, 15, 23, 24 (current.adf.dir), 13 rawToAmigaInt, 7, 9, 15, 23, 24 read.adf, 25, 27 displayRawData, 7, 9, 14, 23, 24 read.adf,ANY-method (read.adf), 25 read.adf,character-method (read.adf), 25 file, 15, 25, 27 read.adz (read.adf), 25
29 30 INDEX read.adz,character-method (read.adf), 25 url, 15, 25 write.adf, 11, 26, 27 write.adf,amigaDisk,ANY-method (write.adf), 27 write.adf,amigaDisk,character-method (write.adf), 27 write.adz (write.adf), 27 write.adz,amigaDisk,character-method (write.adf), 27